Impact of climate and land use change on water availability and reservoir management: scenarios in the Upper Aragón River, Spanish Pyrenees

Streamflows in a Mediterranean mountain basin in the central Spanish Pyrenees were projected under various climate and land use change scenarios. Streamflow series projected for 2021-2050 were used to simulate the management of the Yesa reservoir, which is critical to the downstream supply of irrigation and domestic water. Streamflows were simulated using the Regional Hydro-Ecologic Simulation System (RHESSys). The results show that increased forest cover in the basin could decrease annual streamflow by 16%, mainly in early spring, summer and autumn. Regional climate models (RCMs) project a trend of warming and drying in the basin for the period 2021-2050, which will cause a 13.8% decrease in annual streamflow, mainly in late spring and summer. The combined effects of forest regeneration and climate change are expected to reduce annual streamflows by 29.6%, with marked decreases affecting all months with the exception of January and February, when the decline will be moderate. Under these streamflow reduction scenarios it is expected that it will be difficult for the Yesa reservoir to meet the current water demand, based on its current storage capacity (476 hm(3)). If the current project to enlarge the reservoir to a capacity of 1059 hm(3) is completed, the potential to apply multi-annual streamflow management, which will increase the feasibility of maintaining the current water supply. However, under future climate and land cover scenarios, reservoir storage will rarely exceed half of the expected capacity, and the river flows downstream of the reservoir is projected to be dramatically reduced.

Epidermal growth factor receptor gene numerical aberrations are frequent events in actinic keratoses and invasive cutaneous squamous cell carcinomas

Epidermal growth factor receptor (EGFR) gene amplification and protein overexpression are common in several cancers. EGFR status has seldom been studied in cutaneous squamous carcinomas (SCCs), or their precursors, actinic keratoses (AKs). We evaluated the presence of EGFR genomic aberrations and EGFR protein overexpression in 25 AKs and 35 invasive SCCs by means of fluorescence in situ hybridization (FISH) and immunohistochemistry. EGFR numerical aberrations were detected in 52% of AKs and 77.1% of SCCs (P = 0.042). EGFR amplification was identified in 12% of AKs and 20% of SCCs. No differences regarding EGFR numerical aberrations were observed when AKs with high-grade dysplasia were compared with SCCs. A good correlation was observed between EGFR numerical aberrations and EGFR overexpression. Our results suggest that EGFR numerical aberrations occur in the early stages of epithelial carcinogenesis in skin, not playing a role in the progression from low-grade SCCs into more aggressive phenotypes.

Treatment of localized persistent plaque psoriasis with incoherent narrowband ultraviolet B phototherapy

PURPOSE

This study evaluated the efficacy of targeted UVB phototherapy treatment of chronic persistent psoratic plaques with localized incoherent UVB phototherapy.

METHODS

Sixteen subjects were enrolled. The final group was composed of eight men and seven women, each having one to seven chronic, stable psoriatic plaques. Each plaque was treated with fluences ranging from 3 to 7 MED using a fibre-coupled incoherent phototherapy device twice weekly for a maximum of 13 sessions. Assessments with a combination of three scores, each on a scale from 0 to 4, for scaling, erythema and induration (SEI score) were performed.

RESULTS

The patients received from 6 to 13 sessions (mean 9.6). The SEI score decreased by 3.3 (p = 0.01). This reduction was equally detected in all subscores. In a few patients, blistering and burning sensation after some sessions were noted.

CONCLUSION

Localized UVB phototherapy is an effective treatment option for persistent plaques of psoriasis. Compared with conventional UVB, localized phototherapy has the added safety benefit of virtually eliminating unwanted exposure of the healthy tissue to UVB.

Review of 26 cases of classical pyoderma gangrenosum: clinical and therapeutic features

BACKGROUND

Classical pyoderma gangrenosum (CPG) is an uncommon, idiopathic, neutrophilic skin disease, generally associated with other skin conditions and systemic diseases, and with several treatment options.

OBJECTIVE

The objective of this review was to know the clinical and therapeutic features of our cases of CPG.

METHODS

Twenty-six cases of CPG were included; 65 episodes of PG and 120 treatment courses were analysed; and the mean follow-up was 4.6 years.

RESULTS

21 cases (80%) had lesions on the lower extremities, 16 (61%) had recurrences, 22 (84%) had some disease associated, and 13 (50%) had autoimmune inflammatory conditions. Cyclosporin A (CSA) was used in 22 (84%) patients and 51 (78%) episodes, and prednisone (PDN) was used in 15 (57%) patients and 26 (40%) episodes.

CONCLUSIONS

CSA efficacy was excellent, with an early response and acceptable toxicity, although it did not seem to have any impact on the incidence of PG recurrences.

Clinical characteristics and psychopathological profile of patients with vulvodynia: an observational and descriptive study

BACKGROUND

Vulvodynia is a fairly common dermatological symptom that often interferes with the personal, social and working activities of affected women and results in a significant loss of their quality of life. It is a persistent and tedious clinical disorder which is often resistant to conventional treatments.

OBJECTIVES

The aim of this study is to evaluate the main clinical signs, associated psychopathological disorders and outcome after antidepressant treatment of patients with vulvodynia.

METHODS

Eighty patients were included. Clinical characteristics and psychopathological profiles were determined by appropriate instruments. The improvement of clinical symptoms after combined antidepressant drug therapy was also evaluated.

RESULTS

Pain (70%), burning (63.7%), dyspareunia (57.5%) and stinging (56.2%) were the most commonly reported symptoms. Most patients (56.5%) showed anxiety, and 52.2% of them were reported as having a depression disorder. When evaluated by psychometric tools, 81.4% of patients scored >150 on the Life Event Scale, which means a risk >50% of suffering an illness in the near future, and patients' scores in the Dermatology Life Quality Index showed higher values than the mean of the Spanish validation group. After 6 months of combined treatment with escitalopram (10-20 mg/day), perfenazine (2-4 mg/day) and amytriptiline (10 mg/day), a complete remission of the clinical symptoms was achieved in 41% of patients. In contrast, only 12% of patients who did not follow drug treatment reported a complete resolution of the clinical symptoms.

CONCLUSIONS

Our results seem to confirm that vulvodynia is associated with psychiatric co-morbidity such as stress and depression. The study highlights that the psychiatric treatment may be a useful option to improve clinical symptoms. Whether these patients should be evaluated for depression or be referred to a psychiatrist, remains to be investigated.

Type 2 NF1 deletions are highly unusual by virtue of the absence of nonallelic homologous recombination hotspots and an apparent preference for female mitotic recombination

Approximately 5% of patients with neurofibromatosis type 1 (NF1) exhibit gross deletions that encompass the NF1 gene and its flanking regions. The breakpoints of the common 1.4-Mb (type 1) deletions are located within low-copy repeats (NF1-REPs) and cluster within a 3.4-kb hotspot of nonallelic homologous recombination (NAHR). Here, we present the first comprehensive breakpoint analysis of type 2 deletions, which are a second type of recurring NF1 gene deletion. Type 2 deletions span 1.2 Mb and are characterized by breakpoints located within the SUZ12 gene and its pseudogene, which closely flank the NF1-REPs. Breakpoint analysis of 13 independent type 2 deletions did not reveal any obvious hotspots of NAHR. However, an overrepresentation of polypyrimidine/polypurine tracts and triplex-forming sequences was noted in the breakpoint regions that could have facilitated NAHR. Intriguingly, all 13 type 2 deletions identified so far are characterized by somatic mosaicism, which indicates a positional preference for mitotic NAHR within the NF1 gene region. Indeed, whereas interchromosomal meiotic NAHR occurs between the NF1-REPs giving rise to type 1 deletions, NAHR during mitosis appears to occur intrachromosomally between the SUZ12 gene and its pseudogene, thereby generating type 2 deletions. Such a clear distinction between the preferred sites of mitotic versus meiotic NAHR is unprecedented in any other genomic disorder induced by the local genomic architecture. Additionally, 12 of the 13 mosaic type 2 deletions were found in females. The marked female preponderance among mosaic type 2 deletions contrasts with the equal sex distribution noted for type 1 and/or atypical NF1 deletions. Although an influence of chromatin structure was strongly suspected, no sex-specific differences in the methylation pattern exhibited by the SUZ12 gene were apparent that could explain the higher rate of mitotic recombination in females.

Cranial fasciitis in an 8-year-old boy: clinical and histopathologic features

Cranial fasciitis is an uncommon benign disorder characterized by a fibroblast-like cell proliferation, observed almost exclusively in children. Clinically, it manifests as a rapidly growing, solitary nodule in the head or neck area. Underlying bone involvement (cranial cortical erosion) is frequently detected. Histopathologic analysis allows differentiation between cranial fasciitis and fibrohistiocytic or even sarcomatous lesions observed in children. Cranial fasciitis is considered to be a reactive, non-neoplastic disorder and is usually cured by a simple excision. An increased awareness of the clinical and histopathologic characteristics of this entity seems important to establish the diagnosis, to adopt an adequate, conservative treatment and to avoid unnecessarily aggressive procedures.

Acquired mucosal indeterminate cell histiocytoma

Indeterminate cell histiocytosis is an exceptional and controversial entity with variable clinical, histopathologic or immunohistochemical findings, sharing morphologic and immunophenotypic features from both Langerhans and non-Langerhans cell histiocytoses. Neoplastic cells express S-100 and CD1a antigens, but lack Birbeck granules. It has been reported in both adults and children, as solitary or multiple cutaneous lesions with rare extracutaneous involvement. We describe a 12-year-old boy with an indeterminate cell histiocytosis manifesting as a solitary verrucous papule on the mucosa of the glans penis. The morphologic features and diagnostic criteria of cutaneous indeterminate cell histiocytic proliferations are reviewed. The possible relationship between indeterminate cell and Langerhans cell histiocytoses is discussed.

Childhood Bullous Pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune blistering disease that is rare in childhood. As in adult BP, antibodies against the 180-kDa antigen (BP180) seem to be involved in the pathogenesis of the disease, but, to date, only a small number of children with the disease have been examined immunologically.

OBSERVATIONS

We report the cases of 4 infants with BP aged 5 to 12 months. All of them had involvement of the hands and feet, and they all achieved a complete remission in less than 6 months when treated with oral prednisolone stearoyl glycolate. Three patients could be examined using antigen characterization techniques. Autoantibodies against the NC16A domain of BP180 were found by immunoblot assay in all 3 and by enzyme-linked immunosorbent assay in 2 of them. Interestingly, although IgA autoantibodies were detected in only 1 of them by indirect immunofluorescence, all of them had IgA autoantibodies, and 2 of the 3 had IgG autoantibodies against NC16A as detected by immunoblot assay. One patient also had IgG autoantibodies against the carboxyterminal domain of BP180.

CONCLUSIONS

IgA-specific antibodies against BP180 were detected in all our patients. These findings further raise the question about the relationship between BP and linear IgA bullous dermatosis, the most common autoimmune blistering disorder in children.

Expression profiles associated with aggressive behavior in Merkel cell carcinoma

Primary neuroendocrine carcinoma of the skin, or Merkel cell carcinoma, is the most aggressive cutaneous neoplasm. In spite of its similarities to small cell carcinomas from other locations, Merkel cell carcinoma shows many peculiarities probably related to its epidermal origin and the etiologic role of UV radiation. We have immunohistochemically investigated 43 markers on a tissue microarray in which 31 surgically resected Merkel cell carcinomas were represented. Of these, 15 patients remained free of disease after removal, whereas 16 developed metastases. Immunoreactivity was scored according to staining intensity and the percentage of positive cells. We found statistically significant correlations between metastatic tumor spread and overexpression of matrix metalloproteinase (MMP) 7, MMP10/2, tissue inhibitor of metalloproteinase 3, vascular endothelial growth factor (VEGF), P38, stromal NF-kappaB, and synaptophysin. Also detected were statistically significant correlations between the expression levels of MMP7 and VEGF, MMP7 and P21, MMP7 and P38, MMP10/2 and VEGF, P38 and synaptophysin, P38 and P53, and P21 and stromal NF-kappaB. These findings may be helpful in predicting the clinical course of Merkel cell carcinoma and are potentially useful for the development of targeted therapies.

Bullous pemphigoid in a patient with psoriasis during the course of PUVA therapy: study by ELISA test

A 65-year-old woman had a history of deep vein thrombosis and depression. Psoriasis was diagnosed in 1986 and various topical and systemic therapies, singly or in combination, were prescribed: tar, topical corticosteroids, cyclosporine, etretinate, and methotrexate. Two courses of oral and one course of bath psoralen plus UVA (PUVA) therapy (cumulative dose, 467 J/cm(2)) and UVB (2.96 J/cm(2)) had been given. In January 1999, she developed a flare of generalized psoriasis. In May 1999, therapy with PUVA (8-methoxypsoralen) plus topical acetonide triamcinolone 0.1% was initiated. At the time, she was taking acenocoumarol, lorazepam, and hydroxyzine chlorhydrate. In August 1999, at session 30, when the dose of UVA was 9 J/cm(2), and the total dose was 205 J/cm(2), a bulla appeared on the dorsum of the toe and was controlled with topical antibiotics. Five further sessions of PUVA were given and a generalized itching bullous eruption appeared all over the body. PUVA was stopped and the patient was hospitalized. On physical examination, extensive psoriatic plaques plus vesicles and bullae on the normal skin and on psoriatic lesions were observed all over the body (Fig. 1). Histopathologic study of a lesion showed a subepidermal vesicle containing fibrin, neutrophils, and a few eosinophils. No sunburn cells were observed (Fig. 2). The direct immunofluorescence (DIF) test of perilesional uninvolved skin revealed immunoglobulin G (IgG) (Fig. 3) and C3 at the dermal-epidermal junction. The DIF study using the patient's skin, previously treated with 1 m NaCl, localized the IgG at both the epidermal and dermal sides of the basement membrane zone (Fig. 4). Bullous pemphigoid (BP) was diagnosed and therapy with prednisone (60 mg/day) was started. The disease was well controlled in 3 weeks. The dose of prednisone was tapered and stopped 20 months later, without any recurrence. Study of the antibodies by the indirect immunofluorescence (IIF) test, using monkey esophagus and guinea pig as substrate, was positive at a titer of 1/160 in September 1999. The titer decreased to 1/10 in January 2000, and was negative in July 2000. An enzyme-linked immunosorbent assay (ELISA) test, performed using the commercial kit MBL, which identifies antibodies directed against epitopes of the extracellular fragment NC16 of antigen 2 of BP, was positive at 15 U/mL (normal value, < 9 U/mL) in September 1999, and negative in July 2000 (Table 1).

Recurrent and self-healing cutaneous monoclonal plasmablastic infiltrates in a patient with AIDS and Kaposi sarcoma

Infection with human immunodeficiency virus (HIV) increases the risk of developing non-Hodgkin lymphoma. Plasmablastic lymphoma (PBL) is a rare variant of diffuse large cell lymphoma that often involves the oral cavity of HIV+ patients. It is characterized by immunoblastic morphology and plasma cell phenotype. Cutaneous involvement in PBL appears to be rare. We report a 44-year-old man with AIDS and Kaposi sarcoma (KS) previously treated with doxorubicin who, following treatment with highly active antiretroviral therapy, developed an erythematous infiltrated nodule on the right arm. Histology showed subcutaneous fat necrosis and clusters of atypical large plasma cells (plasmablastic cells). Immunohistochemistry revealed lambda light chain restriction. Epstein-Barr virus (EBV) mRNA was detected by in situ hybridization within the plasmablastic cells. Polymerase chain reaction amplification with specific primers for human herpesvirus 8 (HHV-8) performed on the skin biopsy specimen detected a specific band. A complete screening (bone marrow biopsy, computed tomographic scan, radiological survey) disclosed no abnormalities. The lesion resolved spontaneously after 3 months. Two years later an infiltrated plaque developed on the abdominal wall. The clinical and histopathological features of this new lesion were similar to those observed 2 years previously. No evidence of extracutaneous involvement was detected. The lesion again resolved spontaneously after 25 days. PBL may be seen in patients with transplants or receiving chemotherapy, but is usually observed in patients with advanced AIDS. The observation of recurrent self-healing EBV- and HHV-8-associated cutaneous monoclonal plasmablastic infiltrates, in a patient with AIDS and KS, expands the clinical spectrum of AIDS-associated plasmablastic lymphoproliferative disorders.

Aggressive multifocal Buruli ulcer with associated osteomyelitis in an HIV-positive patient

Mycobacterium ulcerans infection causes a skin disease known as Buruli ulcer (BU), a disorder manifested usually as a solitary and painless nodule or papule that progresses to massive necrotizing destruction and cutaneous ulceration. When healing occurs, it often results in disabling deformities. Buruli ulcer is considered the third most common mycobacterial disease in immunocompetent people, after tuberculosis and leprosy. Although the emergence of Buruli ulcer in Western African countries over the past decade has been dramatic, it has been scarcely reported in industrialized countries. We report a patient from Equatorial Guinea who was human immunodeficiency virus-positive, presenting aggressive and multifocal BU associated with an underlying destructive osteomyelitis, in which only an aggressive surgical approach yielded to a resolution of the disease. In a global world, with increasing migratory population fluxes, an increased awareness of dermatologists regarding the clinical, histopathological and microbiological features of BU is important in order to avoid significant delays in diagnosis and treatment.

Erythrokeratoderma variabilis-like ichthyosis in Chanarin-Dorfman syndrome

Neutral lipid storage disease (Chanarin-Dorfman syndrome) is an autosomal recessive metabolic disorder associated with congenital ichthyosis and a multisystemic accumulation of neutral lipids (lipid droplets) in various types of cells. The clinical presentation has been reported to correspond to that of nonbullous congenital ichthyosiform erythroderma. We report a 4-year-old boy presenting a generalized ichthyosiform disorder manifested by migrating scaly plaques alternating with areas of normal-looking skin, showing erythematous borders with sharp margins, clinically suggestive of erythrokeratoderma variabilis (EKV). A peripheral blood smear revealed cytoplasmic vacuoles in most granulocytes. Genetic studies from the patient and his parents revealed that the patient carried two different and novel mutations of the ABHD5 gene: a nonsense mutation in exon 6 (transmitted by the father) and an insertion/deletion in exon 4 (transmitted by the mother). Our observation demonstrates the clinical heterogeneity of the ichthyosiform dermatoses observed in Chanarin-Dorfman syndrome and widens the clinical range of conditions presenting migrating scaly plaques mimicking EKV.

Acanthosis nigricans as an adverse effect of highly active antiretroviral therapy in an adolescent girl with human immunodeficiency virus infection

We report an 11-year-old girl with acanthosis nigricans that appeared after 4 years of treatment with didanosine, stavudine and amprenavir. Laboratory studies showed hyperglycemia, hyperinsulinemia and hypertriglyceridemia. Withdrawal of amprenavir resulted in disappearance of acanthosis nigricans and improvement of metabolic abnormalities.

Prognostic significance of p27Kip1, p45Skp2 and Ki67 expression profiles in Merkel cell carcinoma, extracutaneous small cell carcinoma, and cutaneous squamous cell carcinoma

AIMS

To compare the immunohistochemical expression of prognostic markers p27(Kip1), p45(Skp2) and Ki67 in Merkel cell carcinoma (primary neuroendocrine carcinoma of the skin, MCC), small cell neuroendocrine carcinoma of lung and urinary bladder (SNC), and cutaneous squamous cell carcinoma (SCC).

METHODS AND RESULTS

Immunohistochemistry was performed using antibodies directed against p27(Kip1), p45(Skp2) and Ki67 on 72 tumour cases: 24 MCC, 25 SCC, and 23 SNC (15 from the lung and eight from the urinary bladder). Percentages of positive cells were determined for each marker and statistically analysed. Expression profiles on MCC and SCC were significantly different for all three markers. MCC and SNC exhibited significant similarities in their p27(Kip1) and p45(Skp2) expression profiles. In contrast, MCC and SNC differed significantly in their Ki67 proliferation indices, which were much higher in SNC. Additionally, MCC cases showed an association between increased proliferation indices and the appearance of local recurrence(s) and/or metastases.

CONCLUSION

The immunohistochemical profile of MCC differs from that of SCC, in spite of their common oncogenesis and the supposed metaplastic origin of MCC, and resembles that of SNC, except for Ki67 levels, which were higher in the latter (characterized by greater biological aggressiveness). High levels of Ki67 also appear to be a prognostic factor in MCC.

Cutaneous alternariosis in transplant recipients: Clinicopathologic review of 9 cases

OBJECTIVES

We sought to evaluate and review the clinical and histopathologic features of cutaneous infections caused by the environmental opportunistic fungus Alternaria observed in transplant recipients.

METHODS

We conducted a retrospective study of cases of cutaneous alternariosis in transplant recipients given a diagnosis in 3 hospitals in Catalonia, Spain, between 1991 and 2001. The clinical and evolution features were reviewed. A panel of histopathologic features was evaluated by two independent observers in all cutaneous biopsy specimens.

RESULTS

In all, 9 transplant recipients (8 men and 1 woman) presenting opportunistic cutaneous alternariosis were studied. The patients were 4 renal, 2 cardiac, 1 liver, and 2 lung transplant recipients. All patients were treated with different immunosuppressive therapeutic regimes. The lesions were solitary (3 patients) or multiple grouped (6 patients): papules (4 patients), plaques (5 patients), inflammatory nodules (2 patients), and recurrent cellulitis with secondary ulceration (1 patient), mainly located on the lower extremities. No extracutaneous involvement was detected. A previous traumatic event was recorded in two patients. A total of 12 cutaneous biopsy specimens were reviewed. Biopsy specimens from early lesions (<3 months evolution) were often characterized by the presence of epidermal changes (3/6 pseudoepitheliomatous hyperplasia; 50%), a diffuse dermal mixed inflammatory infiltrate of lymphocytes, plasma cells, histiocytes, neutrophils, and giant cells, and rare and focal granuloma formation. Dermal abscess or necrotizing folliculitis was occasionally noted. In biopsy specimens from more advanced lesions (>3 months evolution), the presence of a granulomatous inflammatory infiltrate was a constant feature. Suppurative granulomas (2/6; 33%) and sarcoidlike granulomas (2/6; 33%) were noted. In all biopsy specimens, fungal structures with a typical round-to-oval, thick refractile wall were identified.

CONCLUSION

Different clinical and histopathologic patterns can be noted in cutaneous alternariosis. Clinically the lesions manifest as solitary or grouped papules, plaques, or nodules mainly involving the lower extremities. Histologically, a relationship between the evolution of the cutaneous lesions and granuloma formation is detected. An increased awareness regarding the clinical and histopathologic features of cutaneous alternariosis in transplant recipients is important to achieve early detection and treatment.

Kikuchi's disease (necrotizing lymphadenitis) with cutaneous involvement associated with subacute cutaneous lupus erythematosus

Necrotizing histiocytic lymphadenopathy (Kikuchi's disease) is a rarely observed clinical entity characterized by fever, and solitary or multiple lymphadenopathy predominantly in the posterior cervical region. Kikuchi's disease has been reported to precede, coexist with or follow the diagnosis of systemic lupus erythematosus. In only rare instances has its association with cutaneous lupus erythematosus without systemic involvement been reported. We report a 45-year-old woman who presented characteristic systemic and cutaneous manifestations of Kikuchi's disease. Several months later, after sun exposure, she developed lesions of subacute cutaneous lupus erythematosus. The American Rheumatism Association criteria for systemic lupus erythematosus were not fulfilled. The possible pathogenic relationships between the two processes are discussed.

Isotretinoin treatment of acne in a patient with Apert syndrome

Apert syndrome is an autosomal dominant disease caused by mutations in fibroblast growth factor receptor (FGFR-2) and characterized by premature fusion of the cranial sutures and early epiphyseal closure. The development of widespread, severe, pustular acne around puberty is a characteristic feature in these patients. The FGFR-2 mutation of Apert syndrome has been described in localized nevoid acne lesions, which have been attributed to somatic mosaicism. Isotretinoin has been reported to be useful in controlling this acne. We report the successful treatment of acne with isotretinoin in a teenager with Apert syndrome and review the pathophysiology of acne in this syndrome.

Acute generalized exanthematous pustulosis induced by terbinafine

Terbinafine is an allylamine fungicidal agent that is widely used for the treatment of onychomycoses and other fungal infections. Adverse effects may occur in more than 10% of patients receiving oral terbinafine, with cutaneous reactions in 2.7%. We describe the development of acute generalized exanthematous pustulosis in a 36-year-old woman who took oral terbinafine.

Acantholytic dyskeratotic naevi following Blaschko's lines: a mosaic form of Darier's disease

Darier's disease (DD) is an autosomal-dominant skin disorder characterized by loss of adhesion between epidermal cells and abnormal keratinization. Several patients with unilateral, linear, 'zosteriform' or localized lesions have been reported. We report three cases of DD in a localized pattern corresponding to mosaicism type 1 according to Happle's classification and review the literature about the genetic cause of DD and DD in a 'zosteriform' pattern.

Ultrastructural features of highly active antiretroviral therapy-associated partial lipodystrophy

Chronic treatment with highly active antiretroviral therapy (HAART) results in a novel variety of partial lipodystrophy, combining lipoatrophic and hypertrophic areas. We have previously reported the histopathological features of this disease and have also shown that adipocyte apoptosis is involved in its origin. With the aim of further elucidating the mechanisms underlying this peculiar disorder, we performed an ultrastructural study of the adipocytes of ten HIV-1-infected patients treated with HAART for 20-42 months. In all ten cases, two main sets of ultrastructural changes were identified. Some adipocytes showed disruption of cell membranes, fragmented cytoplasmic rims, irregular cell outlines, and eventually fat droplets laying free in the connective tissue, with a histiocytic reaction around them. In addition, many adipocytes showed variable compartmentalization of fat droplets with decrease in cell size and abundant, mitochondria-rich cytoplasm. Often, a dual "white and brown" fat appearance was observed with a large unilocular vacuole surrounded by a rim of multilocular cytoplasm containing smaller isometric fat droplets and numerous mitochondria. These findings suggest that HAART-associated partial lipodystrophy is probably the result of a remodeling process of fat cells involving variable combinations of apoptosis, defective lipogenesis, and increased metabolic activity in different adipose areas of the body.

Merkel cell (primary neuroendocrine) carcinoma of the skin with nodal metastasis showing rhabdomyosarcomatous differentiation

BACKGROUND

We describe a unique case of Merkel cell (primary neuroendocrine) carcinoma of the skin with a lymph node metastasis showing rhabdomyosarcomatous differentiation. Skeletal muscle differentiation has occasionally been described in primary small cell neuroendocrine carcinomas and considered a form of dual differentiation rather than a collision tumor. In the present case, capacity for divergent differentiation appeared late in the course of the tumor, which suggests a clonal origin for both components of the neoplasm.

CONCLUSIONS

The coexistence of neural and rhabdomyoblastic types of differentiation, best epitomized by the Triton tumor, has been construed as the product of dual differentiation of cells originated from neural crest-derived ectomesenchyme. Since Merkel cells seem to originate from a pluripotential primitive keratinocyte and not from the neural crest, rhabdomyoblastic differentiation in a metastasis of primary neuroendocrine carcinoma of the skin probably reflects the close proximity between the programs of neural and skeletal muscle differentiation, which would have been sequentially activated in the case we are reporting.